import 'dart:async';

import 'package:flutter/foundation.dart';

import '../../core/app_version.dart';
import '../../data/models/update_info.dart';
import '../../data/services/native_bridge.dart';
import '../../data/services/update_service.dart';

/// Non-blocking update check against the public Gogs releases API.
class UpdateController extends ChangeNotifier {
  UpdateController(this._platform, {UpdateService? service})
    : _service = service ?? UpdateService();

  final LauncherPlatform _platform;
  final UpdateService _service;

  UpdateInfo? _result;
  bool _checking = false;
  bool _installing = false;
  bool _started = false;
  bool _disposed = false;
  String? _error;
  String? _installMessage;

  String get currentVersion => appVersion;

  String? get latestVersion => _result?.latestVersion;

  bool get checking => _checking;

  bool get updateAvailable => _result?.available ?? false;

  bool get installing => _installing;

  String? get installMessage => _installMessage;

  String? get error => _error;

  String? get releasePageUrl => _result?.releasePageUrl;

  Future<void> start() async {
    if (_started) return;
    _started = true;
    await check();
  }

  Future<void> check() async {
    if (_checking) return;
    _checking = true;
    _error = null;
    _installMessage = null;
    _notify();
    try {
      _result = await _service.check(appVersion);
    } on UpdateException catch (problem) {
      _error = problem.message;
    } catch (_) {
      _error = 'Could not check for updates.';
    } finally {
      _checking = false;
      _notify();
    }
  }

  Future<void> installUpdate() async {
    final result = _result;
    if (_installing || result == null || !result.available) return;
    _installing = true;
    _installMessage = 'Downloading update…';
    _error = null;
    _notify();
    try {
      final installed = await _platform.downloadAndInstallUpdate(
        result.downloadUrl,
      );
      _installMessage = installed.message;
      if (!installed.started && !installed.permissionRequired) {
        _error = installed.message ?? 'Could not start the update installer.';
      }
    } catch (_) {
      _error = 'Could not download the update.';
    } finally {
      _installing = false;
      _notify();
    }
  }

  Future<bool> openReleasePage() {
    return _platform.openUrl(
      _result?.releasePageUrl ?? UpdateService.releasePageUrl,
    );
  }

  void _notify() {
    if (!_disposed) notifyListeners();
  }

  @override
  void dispose() {
    _disposed = true;
    super.dispose();
  }
}